Generally, prior art rocker arms formed from sheet metal are provided with an opening in the center, flat section and then bent to a U-shape. The U-channel can be oriented up or down and is provided with an opening or “window” at the center, either for a pivot attachment or for mounting a rolling element bearing. The window is made by punching out the material and discarding the punched out portion.
Prior art rocker arms stamped from sheet metal typically have a U-shaped lateral cross-section and have no cross members between opposing sides. Under load or when stressed these rocker arms deflect such that opposing sides move outward and their ends move upwards, resulting in a loss of longitudinal stiffness. Lack of stiffness in rocker arms detracts from efficiency especially when operating at high engine speeds. The buckling, insufficiency of rocker arm stiffness also detracts from the capability to achieve maximum engine power.
Accordingly, there is a definite advantage in providing an economical and expeditious means for providing a sheet metal rocker arm possessing greater relative stiffness by an improved construction configuration.